1980’s Mystery - Gas Line Size for Pool Heater

[adambca]

I have a mystery hopefully someone can help with.

I recently purchased a home with a Citadel III pool heater (branded Anthony Pools), which is located about 17 feet from the gas main. Photo attached; built in 1985.

This pool heater is about the same age as the home, so likely was part of the initial build.

The heater worked fine during the home inspection, but has since developed a gas leak. The gas company red tagged it and said the control bypass was malfunctioning.

The home warranty sent a technician out who said this would not be covered because the heater had a 3/4 inch gas pipe running to it from the main, and that this was insufficient for this size heater. He is saying a 1’-1/2” pipe is required. As such, he said, lack of proper gas damaged the unit.

I find this hard to believe, because Anthony Pools installed this as part of the home build, so they wouldn’t run the wrong size pipe for their own equipment. Also, the local building inspector would have had to review the plans and the final before signing off, and they would have called that out. I also find it hard to believe that this size gas line damaged the unit, as it was able to last 35 years.

The challenge is I can’t locate the manual for this pool heater that would show its requirements, and I also can’t find any building code documentation from 1985 to show that 3/4 inch pipe was fine back then for that long of a run.

Does anyone have any data points or ideas?

 

[cowboycasey]

when I searched for that heater the very first hit is the Anthony pool site.. have you called them and asked for the manual? they should still have it.. while you are at it ask them if 3/4 inch pipe was the normal for that install..

Those companies technicians job is not to help you, it is to help the company not pay... anything that can be used to not pay will be used against you.. The problem being is current laws and standards will need to be used to reinstall a new heater.. That means a new line will need to be run or a heater than can use a 3/4 line be installed... I guarantee they will not install a new heater and a new line, it is not happening...

 

[Bperry]

when I searched for that heater the very first hit is the Anthony pool site.. have you called them and asked for the manual? they should still have it.. while you are at it ask them if 3/4 inch pipe was the normal for that install..

Those companies technicians job is not to help you, it is to help the company not pay... anything that can be used to not pay will be used against you.. The problem being is current laws and standards will need to be used to reinstall a new heater.. That means a new line will need to be run or a heater than can use a 3/4 line be installed... I guarantee they will not install a new heater and a new line, it is not happening...

Yep, home warranty policies are the worst scam out there. I paid extra on mine for “pool equipment coverage” got an inspection and they still denied every claim I had for a bad pump and filter that sprung a leak.

 

[JamesW]

Can you show the gas line going to the heater and the whole heater?

 

[adambca]

Actually I think maybe I found the confusion. There is a short 3/4 nipple to a 1 1/2 pipe, and there is 1 1/2 pipe all the way to the heater. The tech from the home warranty company said this would cause the pool heater not to work correctly.

However, another plumber I had over said 3/4 is allowed within 18 inches of the main, and the physics of gas mean that this doesn’t matter. The gas compresses to a higher pressure momentarily as it passes through the 3/4, but then it goes into the 1 1/2 and expands.

I actually noticed that a few pool heaters have a 3/4 inlet, so they have a reducer on their side.

Does this sound right?

I asked for the home warranty company to send out another tech…he is coming on Tuesday so any firepower/references would be appreciated.

 

[JamesW]

3/4" SCH 40 Galvanized Steel Pipe has an Outer Diameter of 1.05”

1" SCH 40 Galvanized Steel Pipe has an Outer Diameter of 1.315”

1-1/4" SCH 40 Galvanized Steel Pipe has an Outer Diameter of 1.66”

1-1/2" SCH 40 Galvanized Steel Pipe has an Outer Diameter of 1.9”

Based on the picture, it looks like the line is 1" or 1-1/4".

If it it 1-1/4", then it is fine up to 100 feet as shown in this chart (Your heater size is 380,000 btu/hr).

If the line is 1", it is borderline too small.

Can you show the gas line coming out of the ground and going into the heater?

What is the model number of your gas meter in CFH?

If it is a 250 CFH model, it is too small.

It needs to be at least 400 CFH just for the heater.

https://images.inyopools.com/cloud/documents/universalh-serieslownox.pdf

https://www.troublefreepool.com/attachments/18f2e90d-d2cd-4413-890a-2aebb47e6c58-jpeg.338589/

 

[JamesW]

Here is a different chart that shows that 1" pipe is ok up to 20 feet.

3/4" pipe can be used up to 5 feet total for the connection to the heater and for transition at the gas meter.

https://s3.amazonaws.com/AWSProd/sites/raypakcom/documents/241236.pdf

Note that pipe lengths are total “equivalent length”.

Equivalent length is the length of pipe plus an “equivalent length” for each fitting.

A 1” 90 has an equivalent length equal to 2.62 feet of 1" straight pipe.

A 1.25” 90 has an equivalent length of 3.45 feet.

For example, a 1.25” pipe with 45 feet of pipe and (5) 90 degrees fittings has an equivalent length of 45 + (5 X 3.45) = 62.25 feet.

 

[JamesW]

Citadel III pool heater (branded Anthony Pools), which is located about 17 feet from the gas main.

If you add about 10 to 20 feet for the vertical pipe and the fittings, the total equivalent length is about 27 to 37 feet.

1" pipe is too small.

1.25" pipe would be fine.

 

[cowboycasey]

@JamesW I love how you come up with things like this.. I am usually great at research but you kick it out of the park

 

[adambca]

Here are some more shots of the gas main. Will post the pool heater side, but as I recall it is the same diameter pipe coming up from the ground, then an elbow, then a reducer to 3/4.

 

[JamesW]

Is there a data tag on the meter?

Is the gas line 1" or 1-1/4" based on the O.D of the pipe?

 

[adambca]

I will check tomorrow, but I believe it is 1 1/4 if I compare the relative size of the 3/4.

What does a data tag look like? Right now it is red tagged.

 

[JamesW]

What does a data tag look like?

It should look something like this with the rating for cubic feet per hour (CFH).

 

[PoolGate]

I'd be curious what the home inspection company put in the report about the gas line for the pool heater when they made the initial inspection. Not sure about yours but for my home inspection it was the inspection company that backed and serviced the home warranty.

 

[ajw22]

Never mind…

 

[JamesW]

The tag I posted was for example.

I don't see a tag on the OP's meter.

 

[adambca]

Will have that measurement soon, but in the meantime, anyone have ideas where I can find additional sources that say it is OK to have a certain length of 3/4 inch pipe, even if ultimately 1 1/4 is required?

A plumber I had out (not the home warranty plumber) said that 3/4 inch was fine as long as it was within 18 inches of the main. And JamesW quoted a manual that said 5’ total 3/4 inches is OK…but looking for any additional documents…for example, municipal code or industry code…have tried googling a few different ways but haven’t found it.

Much appreciated!

 

[MITBeta]

Ultimately, you want less than 0.5 inches of water column pressure drop from the main to the appliance when the appliance is at full fire.

There are plenty of online calculators to figure this out. Calculate the pressure drop across each segment of each diameter pipe in sequence and add them all up.

Or, since the line is already built, simply measure the pressure at each end of the pipe while the heater is running and observe whether the pressure drop falls within an adequate range.

 

[adambca]

I don’t think I have the equipment to measure that, but will let the next inspector know. Here are some more shots of pipe sizing. It seems anyway that the gas line coming from right near the main is 3/4 inch, and the pine coming from the gas company into my box is only 1/2 inch anyway. So I don’t see what the big deal is … there has to be an “expander” somewhere. The gas company box doesn’t have a 1.25” “out”.

 

[adambca]

OK so I measured all the pipe.

I have 3.6” of 1/2” pipe from the gas company “riser” to the gas meter. Then it is 25” of 3/4” pipe to the “expander”. Then 24.5’ of 1 1/4 inch pipe to the pool heater reducer. Then 8” of 3/4 inch pipe into the pool heater itself. That assumes the gas line is buried 6” below the concrete.

I looked at a few calculators, but it seems I don’t have all the variables they want. Any tips on a good calculator and missing variables?